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Pulmonary Embolism — Clinical Guidelines

⚠️ Important update: The 2026 AHA/ACC/ACCP/ACEP/CHEST/SCAI/SHM/SIR/SVM/SVN Guideline for the Evaluation and Management of Acute Pulmonary Embolism in Adults was published in March–April 2026 (PMID 41712677 / 41712898), superseding the ESC 2019 guidelines. Key new feature: the AHA/ACC Acute PE Clinical Categories replacing the classic massive/submassive/low-risk taxonomy.

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1. Epidemiology & Pathophysiology

• Right ventricular pressure overload → RV dilation and failure
• Ventilation-perfusion mismatch → hypoxemia
• Reduced left ventricular preload → hypotension and distributive shock in massive PE

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2. Clinical Presentation

• Presentation ranges from asymptomatic to cardiac arrest (PEA is the most common arrest rhythm in PE).
• Fever >38.6°C suggests infection rather than PE-related infarction.
• Saddle embolus can completely obstruct the right ventricular outflow tract (Fig. 74.7 — Rosen's EM).

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3. Risk Stratification & Pre-Test Probability

Wells Score (PE version)

• <2: Low | 2–6: Intermediate | >6: High
• Dichotomized: ≤4 = PE unlikely; >4 = PE likely

Revised Geneva Score

• 0–3: Low | 4–10: Intermediate | >10: High

PERC Rule (Rule-Out Criteria)

1. Age <50
2. Pulse <100
3. SpO₂ >94%
4. No unilateral leg swelling
5. No hemoptysis
6. No recent trauma or surgery
7. No prior PE/DVT
8. No hormone use

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4. Diagnostic Testing

D-Dimer

• Sensitivity 95–98%, specificity 40–55%
• Use in non-high pre-test probability (gestalt <40%, Wells ≤5, or Revised Geneva ≤4)
• Age-adjusted threshold: (age × 10 µg/L) in patients >50 years reduces false positives without sacrificing safety
• YEARS algorithm: Uses 3 clinical criteria (DVT signs, hemoptysis, PE as most likely dx) + D-dimer; allows higher D-dimer cutoff (1000 ng/mL) when no criteria are met

CT Pulmonary Angiography (CTPA)

• Preferred confirmatory test for PE
• High sensitivity and specificity; identifies alternative diagnoses
• Indicated when D-dimer is elevated or pre-test probability is high

Ventilation-Perfusion (V/Q) Scan

• Used when CTPA is contraindicated (renal failure, contrast allergy, pregnancy)
• In pregnancy: halve the perfusion dose; no ventilation scan needed if perfusion is normal

Echocardiography

• Adjunct for RV strain assessment (RV dilation, paradoxical septal motion)
• Bedside echo useful in hemodynamically unstable patients
• Can show direct thrombus in main pulmonary artery (rare)

Troponin & BNP/NT-proBNP

• Elevated in RV myocardial injury → higher risk of in-hospital decompensation
• Used for sub-stratification of intermediate-risk PE

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5. Severity Classification

Classic (ESC/Historical)

2026 AHA/ACC New Categories

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6. Treatment

Anticoagulation (Foundation of Treatment)

• Provoked (reversible trigger): 3 months
• Unprovoked or persistent risk factor: ≥3 months; reassess for indefinite therapy
• Active malignancy: DOAC (rivaroxaban, apixaban, edoxaban) preferred over LMWH

Systemic Thrombolysis

• Alteplase (tPA): 100 mg IV over 2 hours (standard regimen)
• Absolute contraindications: prior intracranial hemorrhage, ischemic stroke <3 months, active bleeding, intracranial neoplasm
• Relative contraindications include recent surgery, prior major surgery, pregnancy

Catheter-Directed Therapy (CDT)

• Catheter-directed thrombolysis (CDT): lower dose tPA directly into thrombus via catheter — lower bleeding risk than systemic thrombolysis
• Ultrasound-assisted thrombolysis (USAT): e.g., EkoSonic system
• Catheter-directed mechanical thrombectomy (suction, fragmentation)
• Indications: intermediate-high risk PE; massive PE when systemic thrombolysis contraindicated
• ESVM 2025 guidelines address interventional approaches (PMID 40587333)

Surgical Embolectomy

• Reserved for massive PE when thrombolysis is absolutely contraindicated or has failed
• High-volume centers with on-site cardiac surgery

IVC Filter

• Indicated when anticoagulation is absolutely contraindicated
• Consider as adjunct in recurrent PE despite therapeutic anticoagulation
• Retrievable filters should be removed once anticoagulation can be resumed

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7. Special Populations

Pregnancy

• PE is a leading cause of maternal mortality (15% of maternal deaths in the US)
• Risk is ~5× higher than in age-matched non-pregnant women
• D-dimer: unreliable during pregnancy (physiologically elevated); pregnancy-adapted YEARS algorithm may help but validation is limited
• Anticoagulant of choice: LMWH throughout pregnancy (DOACs and warfarin are contraindicated)
• Imaging: V/Q scan or CTPA (both acceptable; halve perfusion dose for V/Q); avoid fetal radiation when possible
• Thrombolysis: considered only in life-threatening massive PE

Malignancy

• Extended anticoagulation required while cancer is active
• DOACs (rivaroxaban, apixaban, edoxaban) preferred over LMWH in most cancer patients

Cardiac Arrest

• IV UFH + CPR; consider empiric thrombolysis if PE suspected and no ROSC
• After thrombolysis: continue CPR for ≥60–90 minutes

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8. PE Response Teams (PERT)

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9. Risk Scores for Prognosis & Early Discharge

PESI (Pulmonary Embolism Severity Index)

• Class I–II (low risk): Consider outpatient or early discharge management
• Class III–V (higher risk): Inpatient management

Simplified PESI (sPESI)

• Age >80
• Cancer
• Cardiopulmonary comorbidity
• HR ≥110
• SBP <100 mmHg
• SpO₂ <90%

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10. Follow-Up

• Repeat imaging at 3–6 months for unprovoked PE (assess clot burden)
• Screen for chronic thromboembolic pulmonary hypertension (CTEPH) if persistent dyspnea at 3–6 months (V/Q scan preferred; echocardiography as screening tool)
• Assess for occult malignancy in unprovoked PE (age-appropriate cancer screening)
• Post-PE syndrome: functional limitation, chronic dyspnea, reduced QoL — may benefit from rehabilitation

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Key References

• 2026 AHA/ACC/ACCP/ACEP/CHEST Guideline — Circulation (PMID 41712677) — de novo comprehensive guideline; introduces AHA/ACC Acute PE Clinical Categories
• 2026 AHA/ACC Guideline — JACC version (PMID 41712898)
• 2025 ESVM Guidelines on Interventional Treatment of VTE (PMID 40587333)
• ACR Appropriateness Criteria — Acute PE Management 2025 (PMID 41193046)
• Rosen's Emergency Medicine, 9e — Chapter 74 (PE)
• Murray & Nadel's Textbook of Respiratory Medicine, 2-Volume Set